Prior art stand assemblies are provided in many applications to form a stable base support for artificial Christmas trees, merchandise display stands, garden umbrellas, and the like. In each of these applications, a pre-fabricated upright pole of usually cylindrical construction is seated into a receptacle in a base of the stand assembly and held therein either by screws, force fit, or some other type of clamping or locking mechanism.
U.S. Pat. No. 4,678,089 to Lang, issued Jul. 7, 1987, discloses a display stand for supporting a tubular upright pole. The open bottom end of the pole is seated over a fixing projection extending upwardly from the bottom of the receptacle, while a centering washer stabilizes the pole at an elevated location. The primary deficiency of the Lang display stand is that, in order for the pole to properly fit within the centering washer and about the fixing projection, the pole must be manufactured to exact tolerances. However, in practice, this is not conveniently possible as prudent business may dictate purchasing the pole from numerous different entities, some of which may base manufacture upon the metric system of measure and others upon the English system of measure. Thus, tolerance variations in the dimension of a pole are certain to occur, which are not adequately addressed in the Lang stand assembly.
U.S. Pat. No. 4,119,290 to Gies, issued Oct. 10, 1978, discloses a stand assembly including three loose piece clamping members supported for sliding movement on a bottom of the stand receptacle. Each clamping member has a sloping exterior surface which reacts against a wedge-shaped setting means. As the setting means is threaded into the receptacle, the clamping members are displaced radially inwardly to clamp on a pole seated in the midst. While the Gies stand assembly is capable of clamping to poles of varying dimensional tolerances, it is a complicated assembly having numerous loose pieces which can be lost or damaged and, by its very design, establishes high frictional forces between the wedging members tending to resist positive and uniform displacement of the clamping members against the pole. Also, the Gies stand is very expensive to produce.
U.S. Pat. No. 1,411,722 to Grenzebach, issued Apr. 4, 1922, discloses a stand assembly including a receptacle which receives a clamping element. The clamping element includes wedge-shaped extensions which react against the side walls of the receptacle to bear inwardly against the pole. The Grenzebach stand assembly is designed to support natural Christmas trees which are relatively heavy. The weight of the natural Christmas tree urges the clamping element downwardly into the receptacles thereby more tightly gripping the surface of the trunk, The Grenzebach stand assembly, however, is unsuitable for artificial Christmas trees, merchandise display stands, or other relatively light structures as the gripping force exerted by the clamping element is dependent upon the weight of the pole and its attendant structures. Also, the Grenzebach stand assembly is designed to release the trunk of the Christmas tree by simply lifting upwardly on the natural Christmas tree, which automatically releases the clamping element. For safety reasons, however, it is desired that artificial Christmas trees, merchandise display stands, and the like be securely fastened to the stand assembly so that deliberate, and intentional release must be undertaken to disassemble the stand assembly from the pole.